Description
This lesson connects a series of activities to examine the physics and dangers of natural and man-made debris traveling through space.

Objectives
Students will:
• Explore the law of conservation of momentum using colliding marbles.
• Investigate how velocity and kinetic energy affect the penetration of a speeding object into a substance.
• Use gelatin to demonstrate how aerogel was utilized by the Stardust mission to capture comet material without damaging it.

Lesson Activities and Sequence
The "Danger: Space Debris" activities needed for this lesson may be found at the websites listed with each activity outlined below:

Collisions
Students will be observing colliding marbles, which demonstrate the law of conservation of momentum. The momentum of a moving object is the product of its mass and its velocity (M = mv). If all of the marbles are identical in mass and size, a moving marble will transfer its momentum to a stationary marble when they collide. (See page 49 of guide.)Keywords: momentum, mass, velocity

Potato Astronaut - Exploration Brief: Micrometeoroids and Space Debris
Part 1: Students will investigate the relationship between velocity and penetration depth when a potato is struck with a plastic straw.
Part 2: Challenge the students to design a way to protect the potato from damage caused by impacts using just the materials they brought to the classroom.Keywords: micrometeroids, space debris, movement

Aerogel-lo - Technology For Studying Comets: Part 3 Aerogel
This activity offers a simple approach for "experiencing" aerogel. Aerogel is an amazing feat of technology that was used by the STARDUST spacecraft to capture high-velocity interstellar dust and particles from the coma of comet Wild 2. This demonstration uses gelatin and pellets to show how STARDUST's aerogel collector captured comet particles. The gelatin is referred to as "aerogel-lo." (Aerogel fact sheet at bottom.)Keywords: comet, collection methods